1024595-77-4Relevant academic research and scientific papers
Stabilization of the hydroperoxido ligand: A 1κO,2κO′ dimetallic coordination mode
Tejel, Cristina,Ciriano, Miguel A.,Jimenez, Sonia,Passarelli, Vincenzo,Lopez, Jose A.
, p. 2093 - 2096 (2008)
(Chemical Equation Presented) A novel coordination mode of the hydroperoxido ligand in which each oxygen atom is bonded to a distinct metal center is present in a rare thermally stable example of this otherwise elusive family of complexes, which was obtained by protonating a bis-peroxido-bridged Rh2 complex. The OOH ligand is displaced by a chloride ion to give the corresponding chlorido-bridged complex (see scheme, L3 = tris(methylenediphenylphosphane)-phenylborate).
Easy access to hydride chemistry on a tripodal P-based rhodium scaffold
Tejel, Cristina,Geer, Ana M.,Jimenez, Sonia,Lopez, Jose A.,Ciriano, Miguel A.
, p. 2895 - 2906 (2012/06/01)
The TBPY-5 rhodium complex [(PhBP3)Rh(CH2=CH 2)(NCMe)] (1; PhBP3 = PhB(CH2PPh 2)3), which contains ethylene in the equatorial plane and a labile acetonitrile ligand at one of the axial positions, provides a simple entry into the chemistry of the fac-[P3Rh] scaffold. DFT calculations using the model compound [(MeB(CH2PMe2) 3)Rh(CH2=CH2)(NCMe)] (1′) reproduce well the crystallographic geometry of 1 and converge to the isolated conformer, in which the strong π back-donation from the metal to the π* orbital of ethylene fixes it coplanar with the equatorial plane. Oxidation of 1 is electrochemically irreversible (at 0.080 V vs SCE), and 1 was effectively oxidized with [Cp2Fe]+ in acetonitrile to [(PhBP 3)Rh(NCMe)3]2+. Reaction of 1 with hydrogen in toluene gives the dihydride [(PhBP3)Rh(H)2(NCMe)] (3), which loses acetonitrile to give the insoluble hydride [{(PhBP 3)Rh(H)(μ-H)}2] (4), while 1 in THF with BHT (2,6-bis(1,1-dimethylethyl)-4-methylphenol) results in the mixed-valence paramagnetic hydride [{(PhBP3)Rh}2(μ-H)3] (5). Complexes 1 and 3 react with oxygen to give the dinuclear complex [{(PhBP3)Rh(μ-O2)}2]. The kinetic products from the protonation of complex 1 with carboxylic acids were found to be the ethyl complexes [(PhBP3)Rh(η1-C2H 5)(κ2-O2CR)] (R = Ph, Me), which establish an equilibrium in solution with the corresponding hydride complexes [(PhBP3)Rh(H)(κ2-O2CR)] (R = Ph, Me) and free ethylene. These equilibria can be shifted to the desired compound working under either an atmosphere of ethylene or vacuum. Sequential protonation of 1 and 3 with HBF4 in acetonitrile gave cleanly the cationic hydride complex [(PhBP3)Rh(H)(NCMe)2]BF4 first and then [(PhBP3)Rh(NCMe)3](BF4)2 and hydrogen. Other electrophiles such as MeOTf react immediately with 1 at one phosphorus atom to give the alkylated (P-methyl) complex [{PhB(PMe)P 2}Rh(κ2-O2SOCF3)].
